George P. Malanson

George P. Malanson
University of Iowa | UI · Department of Geographical & Sustainability Sciences

PhD

About

243
Publications
36,843
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Introduction

Publications

Publications (243)
Article
Refugia will be important to the response of alpine vegetation to climate change. Potential refugia exist at multiple scales, including a range-wide mesoscale. The climates of alpine grasslands of 23 mountain ranges of southern and central Europe were evaluated to assess whether each range would support potential refugia in projected future climate...
Article
Full-text available
The importance of environmental difference among sites and dispersal limitations of species to the explanation of diversity differs among biological systems and geographical regions. We hypothesized that climate and then dispersal limitation will predominantly explain the similarity of alpine vegetation at increasing distances between pairs of regi...
Book
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This is a collection of studies published in the Frontiers in Ecology and Evolution, edited by Shen ZH, Malanson GP, Zhang JL, and Yao M. The eBook was produced by the open assess publisher Frontiers. This eBook is composed of one minireview-editorial by Shen et al., and eleven empirical studies with diversified content and approaches.
Article
Full-text available
Aim Alpine ecosystems differ in area, macroenvironment and biogeographical history across the Earth, but the relationship between these factors and plant species richness is still unexplored. Here, we assess the global patterns of plant species richness in alpine ecosystems and their association with environmental, geographical and historical facto...
Article
Current research on vegetation makes a difference in people’s lives. Plant community classification is a backbone of land management, plant communities are changing in response to anthropogenic drivers, and the processes of change have impacts on ecosystem services. In the following progress report, we summarize the status of classification and rec...
Article
Aim Alpine habitats support unique biodiversity confined to high‐elevation areas in the current interglacial. Plant diversity in these habitats may respond to area, environment, connectivity and isolation, yet these factors have been rarely evaluated in concert. Here we investigate major determinants of regional species pools in alpine grasslands,...
Article
Questions What are the functional trade‐offs of vascular plant species in global alpine ecosystems? How is functional variation related to vegetation zones, climatic groups and biogeographic realms? What is the relative contribution of macroclimate and evolutionary history in shaping the functional variation of alpine plant communities? Location G...
Article
Full-text available
Vegetation ecology is an important component of the human dimensions of the Ecological Society of America (ESA) because it is concerned with ecosystem services and ecosystems as potential natural hazards, which are important for the management of natural and modified landscapes. Moreover, its elements respond to the five major drivers of global cha...
Preprint
The floras of mountain ranges, and their similarity, beta diversity, and endemism, are indicative of processes of community assembly; they are also the initial conditions for coming disassembly and reassembly in response to climate change. As such, these characteristics can inform thinking on refugia. The published floras or approximations for 42 m...
Article
Full-text available
Observations of diversity in alpine vegetation appear to be scale dependent. The relations of plant species richness with surface processes and geomorphology have been studied, but patterns of beta diversity are less known. In Glacier National Park, Montana, diversity has been examined within 1 m² plots and for 16 m² plots across two ranges, with w...
Article
A seminal paper in biogeography is reviewed. Whittaker’s 1956 paper in Ecological Monographs introduced gradient analysis as a conceptual framework. This approach replaced community classification as the preferred methodology among US ecologists and biogeographers. It later developed into the foundation for species distribution modeling. Although t...
Article
Full-text available
Understanding the full range of biodiversity patterns from local to global scales, through the study of the drivers of multiscale plant community composition and diversity, is a current goal of biogeography. A synthetic understanding of to what extent vegetation compositional patterns are produced by biotic factors, geography, or climate and how th...
Article
Expectations of the impacts of climatic variation on species can depend on whether and how intraspecific variability is incorporated in models. Coefficients of variation from tree-ring records of Pinus albicaulis through time and across space were used to parameterize volatility and individuality, respectively. The records across sites were used to...
Preprint
Understanding the full range of biodiversity patterns from local to global scales, through the study of the drivers of multiscale plant community composition and diversity, is a current goal of biogeography. A synthetic understanding of to what extent vegetation compositional patterns are produced by biotic factors, geography or climate and how the...
Article
Mountain plant communities are thought to be sensitive to climate change and, thus, able to reveal its effects sooner than others. The status as sentinels of two plant communities are reviewed. Alpine treeline ecotones and alpine vegetation have been observed to respond to climate change in recent decades. The treeline has moved upslope and alpine...
Article
Mountain plant communities are thought to be sensitive to climate change and, thus, able to reveal its effects sooner than others. The status as sentinels of two plant communities are reviewed. Alpine treeline ecotones and alpine vegetation have been observed to respond to climate change in recent decades. The treeline has moved upslope and alpine...
Article
Full-text available
Drivers of alpine plant community composition have been observed to vary with scale. Diversity of alpine tundra across four regions of the Rocky Mountains and among plots within one region was examined relative to temperature and precipitation variables. For regional scale analyses, averages of three metrics of plot-level species diversity relative...
Article
Motivated by the importance of understanding the dynamics of the growth and dispersal of plants in various environments, we introduce and analyze a discrete agent-based model based on a birth-jump process, which exhibit wave-like solutions. To rigorously analyze these traveling wave phenomena, we derive the diffusion limit of the discrete model and...
Article
The role of intraspecific variability is being examined to improve predictions of responses to climate change or invasions and in research on diversity. Simultaneously, the probability and implications of increased high-frequency climate variability have been raised. An agent based model simulated two species on an environmental gradient representi...
Article
Models of dispersal for response to global climate change can refer to theory on traveling waves developed for invasions. The relevance of this theory may depend on its density- versus habitat-dependence, but it has not considered environmental gradients nor related feedbacks. An agent based simulation model (ABM) for a plant species or vegetation...
Article
Full-text available
Background Variability added to directional climate change could have consequences for ecotone community responses, or positive and negative variations could balance. The response will depend on interactions among individuals along environmental gradients, further affected by stress gradient effects. Methods Two instantiations of the stress gradie...
Article
Increases in climate variability, including extremes, may be expected with anthropogenic climate change, but some evidence is contrary. The issue is important because the consequences of variability can be critical for ecosystems. It has long been known and often rehearsed that ecological consequences of increased variability may be greater than th...
Article
Differences in plant communities are a response to the abiotic environment, species interactions, and dispersal. The role of geographic distance relative to the abiotic environment is explored for alpine tundra vegetation from 319 plots of four regions along the Rocky Mountain cordillera in the USA. The site by species data were ordinated using non...
Chapter
The term “biome” is a level of biological classification with the most straightforward definition but the most varied applications. It is the unit of biogeography one conceptual step below the planetary biosphere, but the degree of division is a matter of choice. The concept is often used to illustrate basic relations between biogeographic patterns...
Article
First introduced to Egypt in 2006, H5N1 highly pathogenic avian influenza has resulted in the death of millions of birds and caused over 350 infections and at least 117 deaths in humans. After a decade of viral circulation, outbreaks continue to occur and diffusion mechanisms between poultry farms remain unclear. Using landscape genetics techniques...
Article
Increasing environmental variability could exacerbate the effects of climate change on ecological processes such as population dynamics, or positive and negative effects (favorable or unfavorable weather) could balance. Such a balance could depend on constraints of the processes. Biological and spatial constraints are represented in a spatially exp...
Chapter
The effects of climate change on species and ecosystems are reviewed in the context of hazards and disasters. Other recent assessments, from other perspectives, are introduced. Examples of past on-ongoing effects of climate change in marine and terrestrial systems, for individual species and for biomes, are presented. Marine examples include sea tu...
Article
Alpine plant communities vary, and their environmental covariates could influence their response to climate change. A single multilevel model of how alpine plant community composition is determined by hierarchical relations is compared to a separate examination of those relations at different scales. Nonmetric multidimensional scaling of species co...
Article
Full-text available
Human outbreaks with avian influenza have been, so far, constrained by poor viral adaptation to non-avian hosts. This could be overcome via co-infection, whereby two strains share genetic material, allowing new hybrid strains to emerge. Identifying areas where co-infection is most likely can help target spaces for increased surveillance. Ecological...
Article
Full-text available
This is a study of migration responses to climate shocks. We construct an agent-based model that incorporates dynamic linkages between demographic behaviors, such as migration, marriage, and births, and agriculture and land use, which depend on rainfall patterns. The rules and parameterization of our model are empirically derived from qualitative a...
Article
Research on the stress gradient hypothesis recognizes that positive (i.e. facilitative) and negative (i.e. competitive) plant interactions change in intensity and effect relative to abiotic stress experienced on a gradient. Motivated by observations of alpine treeline ecotones, we suggest that this switch in interaction could operate along a gradie...
Article
The floras of mountain ranges, and their similarity, beta diversity and endemism, are indicative of processes of community assembly; they are also the initial conditions for coming disassembly and reassembly in response to climate change. As such, these characteristics can inform thinking on refugia. The published floras or approximations for 42 mo...
Article
How does the stress-gradient hypothesis affect coexistence in relation to established theory? For two orthogonal stress gradients, a spatially explicit agent based simulation is used to project diversity for simple competitive and facilitative interactions and for three variations of the stress-gradient hypothesis: intraspecific and interspecific c...
Article
Alpine treeline ecotones are expected to respond to climate change with shifts in biomass patterns and carbon dynamics; however, the nature of these shifts and the current structure of carbon storage at treeline remain poorly understood. Biomass at treeline sites in Glacier National Park (GNP), Montana was measured in different aboveground carbon p...
Article
Multiple environmental factors contribute to the spatial and compositional character and elevational patterns of alpine treeline ecotones (ATEs), and the relative influence of these factors is scale dependent and spatially variable. Frameworks detailing the hierarchical structure of the ATE have been developed to characterize scale dependencies of...
Article
Projections indicate that alpine tundra-specific vegetation may begin to disappear as global warming persists. We develop a context for possible changes to inform modeling, monitoring and mitigation strategies. We ask the degree to which similarity of floras is associated with climatic differences versus geographic distance and pattern among 56 mou...
Article
The stress-gradient hypothesis states that individual and species competitive and facilitative effects change in relative importance or intensity along environmental gradients of stress. The importance of the number of facilitators in the neighborhood of a potential beneficiary has not been explored. Evenly distributed and stress-correlated facilit...
Article
The effects of extended climatic variability on agricultural land use were explored for the type of system found in villages of northeastern Thailand. An agent based model developed for the Nang Rong district was used to simulate land allotted to jasmine rice, heavy rice, cassava, and sugar cane. The land use choices in the model depended on likely...
Conference Paper
Full-text available
Background/Question/Methods In some Rocky Mountain treeline ecotones, whitebark pine (Pinus albicaulis) serves as tree island initiator more frequently than Engelmann spruce (Picea engelmannii) or subalpine fir (Abies lasiocarpa). Whitebark pine mortality from white pine blister rust (pathogen = Cronartium ribicola) reduces opportunities for faci...
Article
Full-text available
By addressing several key features overlooked in previous studies, i.e. human disturbance, integration of ecosystem- and species-level conservation features, and principles of complementarity and representativeness, we present the first national-scale systematic conservation planning for China to determine the optimized spatial priorities for biodi...
Article
Full-text available
At some alpine treelines in the Rocky Mountains, whitebark pine (Pinus albicaulis)—a keystone species—plays a central role in tree island development through facilitation. Whitebark pine occurs both as a solitary tree and also as a component of tree islands, although relative importance of these two patterns varies geographically. We examine the ut...
Article
The area increment of land surface compared with its projected area is an effect of topographic relief and is also a source of environmental variations. To examine the effects of topography and data resolution on surface area calculation, we calculated incremental area coefficients (IACs), based on two different algorithms, for a DEM of China at a...
Article
The concept and use of systems' in geography has had a difficult history. While it is considered to be at the core of physical geography, systems thinking has never united the discipline. Stoddart's (1965) exhortation reveals some of the reasons for both the allegiance to the concept and the difficulties in putting it into practice. In 1965 the fis...
Data
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Article
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This editorial is the product of the Progress in Physical Geography lecture at the April 2013 meeting of the Association of American Geographers. The paper was presented by George Malanson, the North American Editor, and the co-authors presented critiques based on a draft. Subsequently, the manuscript was developed and revised based on discussion a...
Article
Biogeography has many connections to people but fewer to human geography. Biogeography is connected to the four dimensions of anthropogenic global change, but most of this research is tied to land-use change. Biogeographers have studied several ways in which land use affects the patterns and dynamics of organisms, mostly in reference to remnants of...
Article
A framework to monitor mountain summit vegetation (The Global Observation Research Initiative in Alpine Environments, GLORIA) was initiated in 1997. GLORIA results should be taken within a regional context of the spatial variability of alpine tundra. Changes observed at GLORIA sites in Glacier National Park, Montana, USA are quantified within the c...
Article
Full-text available
The exotic disease white pine blister rust (caused by Cronartium ribicola) damages and kills whitebark pine (Pinus albicaulis), even in the extreme environments of alpine treeline communities. We surveyed P. albicaulis trees and tree islands for blister rust in 2 distinct alpine treeline communities in Montana, USA, and examined meso-and microtopog...
Article
Because alpine tundra is responding to climate change, a need exists to understand the meaning of observed changes. To provide context for such interpretation, the relevance of niche and neutral theories of biogeography and the continuum and classification approaches to biogeographic description are assessed. Two extensive studies of alpine tundra,...
Article
Full-text available
The position of treeline has been attributed to climatic factors affecting trees, and some studies mention soils. No studies, however, examine treeline as a limit for tundra vegetation; the treeline is also the tundra-line. The position of treeline on an elevation gradient is examined in relation to soil fertility. Soils were sampled at 25 treeline...
Article
The mechanisms that determine the location of the upper altitudinal limit of tree species' survival are not completely understood. We test one hypothesis of treeline location, the carbon balance hypothesis, using a physiologically mechanistic forest process model to simulate carbon balance along elevational transects across the alpine treeline eco-...
Article
Short term change in the relations of land cover (LC) and soil organic carbon (SOC) are a challenge for management requiring a modeling methodology for monitoring annual transitions in the SOC. As part of this methodology, ‘annual land cover change information’, available from remote sensing is assimilated within an ecosystem modeling framework. In...
Chapter
Invasive plant species are a threat to the native plants of the Galapagos, including the many endemics. The botany program at the Charles Darwin Research Station has identified guava, blackberry, and elephant grass.
Article
Theoretical and empirical evidence exists for a positive relationship between environmental heterogeneity and species diversity. Alpine plant communities can exhibit exceptional diversity at a fine scale, which niche theory would suggest is the result of fine scale spatial heterogeneity of the environment. To test if species diversity of alpine pla...
Article
Because the distribution of alpine tundra is associated with spatially limited cold climates, global warming may threaten its local extent or existence. This notion has been challenged, however, based on observations of the diversity of alpine tundra in small areas primarily due to topographic variation. The importance of diversity in temperature o...
Article
Alpine treelines can be explained by lower temperatures with increasing elevation at global scales, but regional and local treelines vary because of additional constraints. We examine data from treelines across the western USA, divided into subregions to elucidate the patterns of these other constraints. We determined the best predictor of elevatio...
Chapter
Full-text available
The pattern of ecotones relative to gradients in the abiotic environment may be affected by spatial biotic positive feedback, i.e., where trees improve the conditions for other trees in their neighborhood. Computer simulation models were used to investigate the consequences of degrees of positive feedback. A hybrid model combining FOREST-BGC, ATE-B...
Article
Full-text available
For over 100 years, mountain treelines have been the subject of varied research endeavors and remain a strong area of investigation. The purpose of this paper is to examine aspects of the epistemology of mountain treeline research-that is, to investigate how knowledge on treelines has been acquired and the changes in knowledge acquisition over time...
Article
This paper describes the design and implementation of an Agent-Based Model (ABM) used to simulate land use change on household farms in the Northern Ecuadorian Amazon (NEA). The ABM simulates decision-making processes at the household level that is examined through a longitudinal, socio-economic and demographic survey that was conducted in 1990 and...
Article
The alpine treeline ecotone in Glacier National Park (GNP) can respond to climate change. An examination of what is known about treelines in general indicates that seedling establishment is the important response to climate change, but this stage is also affected by many other variables. In GNP, the importance of protected sites generated by local...
Article
Impending risks associated with climate change have forced the global community to devise tradable pollution permit or “cap and trade” approaches to control the release of greenhouse gases. In the U.S, soils have the potential to offset about 10 percent of annual CO2 emissions; however, if carbon credits are to be included in greenhouse gas control...
Chapter
Full-text available
Spatial biotic positive feedback, that is, where trees improve microclimatic conditions for other trees, can influence ecotone patterns and processes. We examined the effects of positive feedback between pattern and tree establishment using computer simulation models validated against a dendrochronological reconstruction of subalpine forest advance...
Article
In order to improve modeling of alpine treeline responses to climate change, estimations of snowfall at treeline sites are needed. The MT-CLIM climate model was evaluated for this purpose by extrapolating precipitation and temperature from standard weather stations at lower elevations to 30 alpine SNOTEL study sites across the western United States...
Article
Land use land cover (LULC) plays an important role in influencing the spatial intensity of water erosion which is the primary governor of horizontal translocation of soil organic carbon (SOC). The fate of redistributed SOC through erosion remains debatable and the mineralization rate of exposed SOC protected in soil aggregates is the major focus of...
Article
Full-text available
The simulation of rural land use systems, in general, and rural settlement dynamics in particular has developed with synergies of theory and methods for decades. Three current issues are: linking spatial patterns and processes, representing hierarchical relations across scales, and considering nonlinearity to address complex non-stationary settleme...
Article
Full-text available
Snow avalanches, snow accumulation, and snow ablation patterns were mapped and analyzed to assess their impact on the three-dimensional position, composition (closed canopy forest, open canopy forest, meadow, krummholz, and non-vegetated surfaces), and spatial structure of the Alpine Treeline Ecotone (ATE) in a portion of Glacier National Park, Mon...
Article
Growth of coniferous trees at alpine treeline locations has traditionally been viewed as primarily temperature dependent. In this study, we use a physiologically mechanistic process model, ATE-BGC (Alpine Treeline Ecotone - BioGeochemical Cycles), to study the effects of a suite of environmental variables on the carbon balance of krummholz growth f...
Article
Two graphical models of plant competition, the ‘ghost of competition past’ and the ‘hierarchical’ model are compared using a greatly simplified individual-based forest dynamics simulation. Assumed fundamental niche shapes are used to determine the basic growth responses of the species, but competition alters the realized niche. Differences in the t...
Article
Full-text available
Studies of feedback between ecological pattern and process can benefit from the analysis of visually striking patterns, as they may reveal underlying processes and clarify the relative role of exogenous versus endogenous factors in driving vegetation change. Roughly linear forest patches are common in subalpine environments, including 'hedges', 'ri...